Re: Panic on 8-node system in memblock_virt_alloc_try_nid()

[Yinghai Lu]

On Thu, Jan 23, 2014 at 2:49 PM, Dave Hansen <dave.hansen@xxxxxxxxx> wrote:
> Linus's current tree doesn't boot on an 8-node/1TB NUMA system that I
> have.  Its reboots are *LONG*, so I haven't fully bisected it, but it's
> down to a just a few commits, most of which are changes to the memblock
> code.  Since the panic is in the memblock code, it looks like a
> no-brainer.  It's almost certainly the code from Santosh or Grygorii
> that's triggering this.
>
> Config and good/bad dmesg with memblock=debug are here:
>
>         http://sr71.net/~dave/intel/3.13/
>
> Please let me know if you need it bisected further than this.

Please check attached patch, and it should fix the problem.

Yinghai
Subject: [PATCH] x86: Fix numa with reverting wrong memblock setting.

Dave reported Numa on x86 is broken on system with 1T memory.

It turns out
| commit 5b6e529521d35e1bcaa0fe43456d1bbb335cae5d
| Author: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
| Date:   Tue Jan 21 15:50:03 2014 -0800
|
|    x86: memblock: set current limit to max low memory address

set limit to low wrongly.

max_low_pfn_mapped is different from max_pfn_mapped.
max_low_pfn_mapped is always under 4G.

That will memblock_alloc_nid all go under 4G.

Revert that offending patch.

Reported-by: Dave Hansen <dave.hansen@xxxxxxxxx>
Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>


---
 arch/x86/include/asm/page_types.h |    4 ++--
 arch/x86/kernel/setup.c           |    2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

Index: linux-2.6/arch/x86/include/asm/page_types.h
===================================================================
--- linux-2.6.orig/arch/x86/include/asm/page_types.h
+++ linux-2.6/arch/x86/include/asm/page_types.h
@@ -51,9 +51,9 @@ extern int devmem_is_allowed(unsigned lo
 extern unsigned long max_low_pfn_mapped;
 extern unsigned long max_pfn_mapped;
 
-static inline phys_addr_t get_max_low_mapped(void)
+static inline phys_addr_t get_max_mapped(void)
 {
-	return (phys_addr_t)max_low_pfn_mapped << PAGE_SHIFT;
+	return (phys_addr_t)max_pfn_mapped << PAGE_SHIFT;
 }
 
 bool pfn_range_is_mapped(unsigned long start_pfn, unsigned long end_pfn);
Index: linux-2.6/arch/x86/kernel/setup.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/setup.c
+++ linux-2.6/arch/x86/kernel/setup.c
@@ -1173,7 +1173,7 @@ void __init setup_arch(char **cmdline_p)
 
 	setup_real_mode();
 
-	memblock_set_current_limit(get_max_low_mapped());
+	memblock_set_current_limit(get_max_mapped());
 	dma_contiguous_reserve(0);
 
 	/*